Backup server in a virtual machine

[firecat53]

Hey. I'm contemplating moving our family backup server from a separate computer to a virtual machine (8.04 server running on vmware) running on our main Vista (sigh) desktop. Is anyone aware of advantages or disadvantages of actually doing the backups to a virtual disk vs backing up to a physical disk? I have a 400G backup drive, but I just can't find any info about the wisdom of using virtual disks for backup storage.

Any thoughts or experiences welcome!!

Thanks, Scott